GB2288240A - Device for detecting the position of a control element - Google Patents

Device for detecting the position of a control element Download PDF

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Publication number
GB2288240A
GB2288240A GB9504437A GB9504437A GB2288240A GB 2288240 A GB2288240 A GB 2288240A GB 9504437 A GB9504437 A GB 9504437A GB 9504437 A GB9504437 A GB 9504437A GB 2288240 A GB2288240 A GB 2288240A
Authority
GB
United Kingdom
Prior art keywords
measuring
housing
pressure medium
control element
control line
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9504437A
Other versions
GB9504437D0 (en
GB2288240B (en
Inventor
Heinz Ruhmer
Peter Buchholz
Nikolaus Wahnschaffe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Volkswagen AG
Original Assignee
Volkswagen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Volkswagen AG filed Critical Volkswagen AG
Publication of GB9504437D0 publication Critical patent/GB9504437D0/en
Publication of GB2288240A publication Critical patent/GB2288240A/en
Application granted granted Critical
Publication of GB2288240B publication Critical patent/GB2288240B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20Other details, e.g. assembly with regulating devices
    • F15B15/28Means for indicating the position, e.g. end of stroke
    • F15B15/2815Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15BSYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20Other details, e.g. assembly with regulating devices
    • F15B15/28Means for indicating the position, e.g. end of stroke
    • F15B15/2815Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • F15B15/2853Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using potentiometers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D25/00Fluid-actuated clutches
    • F16D25/12Details not specific to one of the before-mentioned types
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/003Measuring arrangements characterised by the use of electric or magnetic techniques for measuring position, not involving coordinate determination
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01LMEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0089Transmitting or indicating the displacement of pistons by electrical, electromechanical, magnetic or electromagnetic means
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60WCONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2710/00Output or target parameters relating to a particular sub-units
    • B60W2710/02Clutches
    • B60W2710/021Clutch engagement state
    • B60W2710/022Clutch actuator position
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16DCOUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2300/00Special features for couplings or clutches
    • F16D2300/18Sensors; Details or arrangements thereof

Description

2288240
-1DESCRIPTION DEVICE FOR DETECTING THE POSITION OF A CONTROL ELEMENT
The present invention relates to a device for detecting the position of a control element which can be influenced hydraulically or pneumatically by means of a control line, having at least one position transmitter.
Control elements which can be influenced hydraulically are used, for example, in actuating devices for friction couplings in motor vehicles, effective between the engine and the gears. From German laid-open document DE 40 11 850 Al. for example, an automatically effective friction coupling is known. This coupling can be engaged and disengaged by means of an actuating mechanism which comprises a disengaging bearing and a fork engaging therewith. The actuating medhanism is in turn actuated by a control member in the form of a hydraulic cylinder which is connected by controllable hydraulic directional control valves to a pressure medium circuit. Furthermore, an electronic control unit is provided which, in dependence upon different parameters, controls the directional control valves of the pressure medium circuit in order, by means of the hydraulic control member, to adjust a corresponding -2coupling engagement. Such parameters are, for example, the engine speed, the position of the throttle valve or the coupling actuation path or the coupling engagement state. In the known actuating mechanism the coupling actuation path or the engagement state is detected by means of a potentiometer disposed directly on the control member, which determines the path and/or position of the piston of the control member and sends a corresponding electrical variable to the electric control unit. In certain applications of such hydraulic control members the direct arrangement of a position or path transmitter can be problematic for reasons of space or because of the necessary electrical supply lines.
The aim of the present invention is to create a device to detect the position of a control element which can be acted upon by pressure, which device is not disposed directly on the control element.
According to the present invention there is provided a device for detecting the position of a control element which can be influenced hydraulically or pneumatically by means of a control line, having at least one position transmitter, comprising a measuring piston slidably located in a housing which is provided, in the control line of the control element, a sensor being provided for monitoring the position of 4 1 -3the_ measuring piston in the housing to thus monitor the position of the control element.
In an advantageous development of the present invention the measuring piston divides the housing into a primary and a secondary chamber, each with at least one flow connection to the control line upon which the pressure medium acts, the piston being prestressed towards its rest position against the pressure of the control medium, which can be influenced. If the control element is then moved from its rest position, the measuring piston is primarily acted upon on the primary chamber side by pressure medium by way of the control line and, operating as a transfer piston, transfers a corresponding displacement by virtue of an adjustable transfer relationship to the control element.
In a preferred embodiment of the device in accordance with the present invention the measuring piston consists of a first and a second partial piston sliding in a sealing manner on the inner wall of the housing, wherein an unpressurised chamber is formed between the partial pistons. In order to relieve pressure the unpressurised chamber advantageously has a flow connection to an equalising reservoir or tank.
In one embodiment, in order to detect the position of the control element, the partial pistons are connected to each other by a measur-Lng rod comprising a measuring scale. In accordance with a development of the embodiment the length of the measuring scale corresponds, according to a transfer relationship, to the displacement path of the control element. The pressure medium transfer can be adjusted by forming the primary and secondary chambers with different diameters.
The measuring scale may be formed by a toothed rod disposed between the partial pistons, which transmits the translatory movement of the measuring piston, for example, to a toothed wheel with which it is engaged, and which converts this movement into a rotary movement which is transferred to a potentiometer.
Another possibility for the detection of the position or displacement path, consists of forming the measuring scale magnetically and carrying out the detection of measuring values inductively.
In addition to the arrangement of the measuring rod between the two partial pistons there is also the possibility of driving this laterally against one of the two partial pistons either by means of the primary or the secondary chamber to the outside, where it is in operational connection with a measuring value sensor.
z The device of the present invention can be used in a particularly advantageous manner to detect a coupling actuation path. The measuring piston sliding in a housing is, for example, disposed in the pressure medium control line of the control cylinder which can be acted upon by the pressure medium.
In the device for actuating a coupling, the measuring piston preferably divides the housing into a primary and a secondary chamber with at least one flow connection, and is prestressed towards its rest state against the pressure of the control medium. which can be influenced, wherein the secondary chamber is connected, when the measuring piston is in the rest position, to a venting passage in the housing.
According to an advantageous embodiment at least one of the valves controlling the flow of pressure medium in the control line forms a construction unit with the housing in which the measuring piston slides, wherein it is possible freely to choose the spatial position of the pressure medium supply unit, with respect to devices, in which the valves are integrated in the pressure medium supply unit and thus the connection line must be disposed upwardly inclined between the measuring piston and valves for the purpose of venting.
However, in addition to the use in a device to -6actuate a coupling there are other uses for the device in accordance with the invention, for example, for valves acted upon by pressure.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is a device constructed according to the present invention for actuating a friction coupling, Figure 2 is cross sectional view of one embodiment of a device according to the present invention for detecting the position of a control element with a mechanical position transmitter; and Figure 3 is a cross sectional view of a device according to the present invention for position detection utilising an inductive position transmitter.
The device illustrated in Figure 1 comprises a friction coupling 18, which connects an internal combustion engine of a motor vehicle to gearing in dependence upon certain operating states or transitions between individual operating states. The friction coupling can be engaged and disengaged by means of an actuating mechanism 14. The actuating mechanism is actuated in turn by a control element 2 in the form of a slave cylinder. The slave cylinder 2 is connected by means of a control line 1 and a directional control valve 20 to a pressure medium -7circuit 21. The pressure medium circuit comprises a pressure medium pump 23 which can be driven by a motor 22 and which is connected to a fluid storage container 24, the pump 23 acting on the slave cylinder 2 by means of the directional control valve 20. Between the pressure medium pump 23 and the directional control valve 20 a non-return valve 25, is located together with a pressure switch 26 which switches the motor 22 on and off according to requirements, and an accumulator 27. The accumulator 27 can be dimensioned in such a way that when the motor vehicle is put into operation at least a first disengagement or supply of energy is possible. Thus no special motor is required for the pressure medium pump 23, the accumulator 27 being supplied during the driving operation, by the pressure medium pump 23 driven by the internal combustion engine 22.
In order to adjust the frictional engagement of the friction coupling 18 an electronic control unit 28 is provided which in dependence upon sensed or preset variables transmits an adjustment variable to the directional control valve 20 to actuate the coupling. The sensed variables are among other things, the engine speed, the throttle valve position and the coupling actuation path or the coupling engagement state. In order to detect the coupling actuation path -8a sensor cylinder 29 is disposed in the pressure medium control line 1 of the slave cylinder 2. The control line 1 thus represents a hydraulic rod which displaces the fluid volume between the slave cylinder 2 and the sensor cylinder 29.
The sensor cylinder 29 shown in more detail in Figure 2, consists of a cylindrical housing 4 which a measuring piston 3 divides into a primary chamber 5 and a secondary chamber 6. Both the primary and secondary chambers 5, 6 are connected to flow connections 7, 8, wherein the primary chamber is connected by the directional control valve 20 to the pressure medium circuit, and the secondary chamber 6 is connected to the slave cylinder 2. The measuring piston 3 is prestressed in its rest position by a compression spring 15 against the action of the pressure medium through the pressure medium circuit. The measuring piston 3 consists of two partial pistons 9 and 10 which slide over sealing rings 17 and 19 provided on the inner wall of the housing 4. A measuring rod 12 comprising a measuring scale 11 formed as teeth, is located between the partial pistons 9, 10 and is fixedly connected to the partial pistons. An unpressurised measuring chamber 16 between the partial pistons 9, 10. in which the measuring rod 12 is located, is connected by a Z -9connection bore 30 to a tank (not illustrated).
By means of a toothed wheel 13 engaging the teeth on the measuring rod 12, any translatory movement of the measuring piston 3 is transformed into a rotary movement and in a known manner is transferred to a rotary potentiometer (not illustrated) wherein the rotary potentiometer produces an electrical output signal which is proportional and therefore linear, to the travelled path of the slave cylinder 2. In order to equalise the pressure or vent the secondary chamber 6 a breather hole bore 31 is provided in the housing 4, which, during passage of the partial piston 10 over the same into the rest position, connects the secondary chamber 6 to a tank or equalising reservoir (not illustrated).
Figure 3 shows an alternative embodiment of the present invention wherein a sensor cylinder with an inductive measuring value sensor is provided. This sensor cylinder has a measuring rod 12 disposed between partial pistons 9 and 10, and is provided with a material 36 which influences the inductivity of a measuring coil 35 disposed in the housing 4, and which in the movement direction has a position marking structure. Each position of the material attached to the measuring rod thus differently influences the inductivity of the measuring coil 35 in a -10characteristic manner. The measuring coil 35 is provided with a constant voltage with a relatively high frequency and, for example, the current flowIng through is measured, wherein this is a measure of the inductivity of the measuring coil 35 and therefore a measure of the momentary position of the measuring piston 3 in the cylindrical housing 4.
C is

Claims (11)

-11CLAIMS
1. A device for detecting the position of a control element which can be influenced hydraulically or pneumatically by means of a control line, having at least one position transmitter, comprising a measuring piston slidably located in a housing which is provided, in the control line of the control element, a sensor being provided for monitoring the position of the measuring piston in the housing to thus monitor the position of the control element.
2. A device as claimed in claim 1, in which the measuring piston divides the housing into a primary and a secondary chamber each with at least one flow connection to the control line, and is prestressed in its rest position against the pressure of the control medium in the control line.
3. A device as claimed in claim 1 or claim 2, in which the measuring piston is formed from a first and a second partial piston sliding in a sealing manner on the inner wall of the housing, and an unpressurised chamber is formed between the partial pistons.
4. A device as claimed in claim 3, in which a measuring rod is disposed laterally at one of the two partial pistons, and is driven out of the housing by way of the primary or secondary chamber, and which, outside the housing, is in operational connection with -12a measuring value sensor in order to form the position transmitter.
5. A device as claimed in claim 3, in which the partial pistons are connected to each other by means of a measuring rod comprising a measuring scale, which is in operational connection with a measuring value sensor in order to form the position transmitter.
6. A device as claimed in claim 5, in which the length of the measuring scale corresponds, according to a transfer relationship, to the displacement path of the control element.
7. A device as claimed in claim 5 or claim 6, in which the measuring scale is formed by a toothed rod disposed between the partial pistons.
8. A device as claimed in claim 7, in which the toothed rod is in operational connection with a toothed wheel, which transfers the movement of the measuring piston to a potentiometer.
9. A device as claimed in any one of claims 1 to 6, in which the position transmitter is formed as an inductive or capacitive measuring value sensor.
10. A device for actuating a coupling of a motor vehicle, in particular by means of a slave cylinder having a pressure medium circuit which comprises at least one pressure medium pump, a driving device actuating the pressure medium pump, an accumulator and- -13valves controlling the flow of pressure medium, the pressure medium control line of the slave cylinder comprising a device as claimed in any one of the preceding claims.
11. A device for detecting the position of a control element which can be influenced hydraulically or pneumatically by means of a control line, having at least one position transmitter. said device being constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
GB9504437A 1994-03-08 1995-03-06 Device for detecting the position of a control element Expired - Fee Related GB2288240B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE4407648A DE4407648C2 (en) 1994-03-08 1994-03-08 Device for detecting the position of an actuator

Publications (3)

Publication Number Publication Date
GB9504437D0 GB9504437D0 (en) 1995-04-26
GB2288240A true GB2288240A (en) 1995-10-11
GB2288240B GB2288240B (en) 1998-09-30

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ID=6512135

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9504437A Expired - Fee Related GB2288240B (en) 1994-03-08 1995-03-06 Device for detecting the position of a control element

Country Status (4)

Country Link
JP (1) JPH0843004A (en)
DE (1) DE4407648C2 (en)
FR (1) FR2717260B1 (en)
GB (1) GB2288240B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2899409A3 (en) * 2014-01-24 2016-04-27 Schaeffler Technologies AG & Co. KG Measuring adapter for a hydraulic line, preferably for a clutch actuation unit of a motor vehicle
IT201700114459A1 (en) * 2017-10-11 2019-04-11 Ognibene Power Spa TRANSDUCER, COMPREHENSIVE DEVICE OF THIS TRANSDUCER AND EQUIPMENT INCLUDING THE DEVICE

Families Citing this family (11)

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DE19542766B4 (en) * 1994-11-25 2004-11-04 Volkswagen Ag working cylinder
FI102413B1 (en) * 1996-04-11 1998-11-30 Lako Forest Oy A system for monitoring the movement of a device driven by a hydraulic cylinder
ES2150832B1 (en) * 1996-06-12 2001-06-16 Fichtel & Sachs Ag OPERATING DEVICE FOR THE OPERATION, IN PARTICULAR PNEUMATIC OPERATION, OF A FRICTION CLUTCH.
FR2756917A1 (en) * 1996-12-09 1998-06-12 Cristini Marcel Louis Michel Tyre pressure measuring mechanism for vehicle
DE19652785B4 (en) * 1996-12-19 2007-01-18 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Release device with integrated displacement sensor for a hydraulically actuated friction clutch
FR2842267B1 (en) * 2002-07-11 2005-09-23 Renault Sa CYLINDER FOR A DEVICE FOR HYDRAULICALLY CONTROLLING A CLUTCH OF A MOTOR VEHICLE
DE102008010703A1 (en) 2008-02-22 2009-08-27 Robert Bosch Gmbh Measuring system for detecting position of piston i.e. valve slide, of piston cylinder unit i.e. valve, has sensor that is arranged such that sensor measures change of magnetic field produced by magnet during rotation of wheel
DE102012214456A1 (en) * 2012-08-14 2014-02-20 Zf Friedrichshafen Ag Displacement measuring device for detecting movement of switching-gear component in e.g. dual clutch transmission of motor car, has induction coil that is fixed in transmission, and shifting claw that is connected with coil core
DE102017219254B4 (en) * 2017-10-26 2020-10-01 Festo Se & Co. Kg Throttle device
CN108386462A (en) * 2018-03-23 2018-08-10 洛阳世英机械制造有限公司 A kind of non-maintaining electro-hydraulic control system of clutch
CN110228062B (en) * 2019-04-19 2021-04-20 武汉智仁传控技术有限公司 Hydraulic system and mechanical arm of rotary electro-hydraulic actuator

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Publication number Priority date Publication date Assignee Title
GB1371869A (en) * 1973-10-01 1974-10-30 Girling Ltd Flowmeters
GB2018999A (en) * 1978-04-11 1979-10-24 Univ Cardiff Distance Measuring
WO1984003763A1 (en) * 1983-03-22 1984-09-27 Hara Ab Potentiometer device for determining the position of hydraulic pistons and the like
GB2164154A (en) * 1984-09-04 1986-03-12 Martonair Ltd Magnetic velocity sensor
GB2202331A (en) * 1987-03-19 1988-09-21 British Gas Plc Electromagnetic transducer
GB2219662A (en) * 1988-06-06 1989-12-13 Daido Metal Co Fluid flow detector
GB2253062A (en) * 1991-02-21 1992-08-26 Mannesmann Ag Potentiometer apparatus for measuring the displacement of a piston in a cylinder

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DE4011850B4 (en) * 1989-04-17 2006-04-27 Luk Lamellen Und Kupplungsbau Beteiligungs Kg A method of controlling an automated friction clutch operative between an engine and a transmission
DE4019747C1 (en) * 1990-06-21 1991-09-19 J.M. Voith Gmbh, 7920 Heidenheim, De
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Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1371869A (en) * 1973-10-01 1974-10-30 Girling Ltd Flowmeters
GB2018999A (en) * 1978-04-11 1979-10-24 Univ Cardiff Distance Measuring
WO1984003763A1 (en) * 1983-03-22 1984-09-27 Hara Ab Potentiometer device for determining the position of hydraulic pistons and the like
GB2164154A (en) * 1984-09-04 1986-03-12 Martonair Ltd Magnetic velocity sensor
GB2202331A (en) * 1987-03-19 1988-09-21 British Gas Plc Electromagnetic transducer
GB2219662A (en) * 1988-06-06 1989-12-13 Daido Metal Co Fluid flow detector
GB2253062A (en) * 1991-02-21 1992-08-26 Mannesmann Ag Potentiometer apparatus for measuring the displacement of a piston in a cylinder

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2899409A3 (en) * 2014-01-24 2016-04-27 Schaeffler Technologies AG & Co. KG Measuring adapter for a hydraulic line, preferably for a clutch actuation unit of a motor vehicle
IT201700114459A1 (en) * 2017-10-11 2019-04-11 Ognibene Power Spa TRANSDUCER, COMPREHENSIVE DEVICE OF THIS TRANSDUCER AND EQUIPMENT INCLUDING THE DEVICE
EP3470798A1 (en) * 2017-10-11 2019-04-17 Ognibene Power S.P.A. Transducer, device comprising said transducer and apparatus comprising said device

Also Published As

Publication number Publication date
JPH0843004A (en) 1996-02-16
FR2717260B1 (en) 1997-10-31
GB9504437D0 (en) 1995-04-26
GB2288240B (en) 1998-09-30
FR2717260A1 (en) 1995-09-15
DE4407648A1 (en) 1995-09-14
DE4407648C2 (en) 1997-09-04

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020306